From the thesis abstract: "Access control of computing systems is considered a key issue among Information Systems managers. There are different methods available to computing systems to ensure a proper authentication of a user. Authentication mechanisms can use simple user-generated passwords to complicated combinations of passwords and physical characteristics of the user (i.e., voice recognition device, retina scanner, signature recognition device, etc.). This thesis looks at the various authentication mechanisms available to a security manager. It describes how different authentication mechanisms operate and the advantages and disadvantages associated with each mechanism. It also reports on several commercially available software products that support the user authentication process. Finally, a discussion of password use in the military environment and the unique requirements of the Department of Defense."
Defense Technical Information Center (DTIC): http://www.dtic.mil/dtic/